Ecological Stewardship
A Common
Reference for Ecosystem Management
Volume !!
• Biological and Ecologlcal Dimensions
• Humans as Agents of Ecological Change
Editors
R.C. Szaro, N.C. Johnson,
A practical
W.T. Sexton & A.J. Malk
reference for scientists
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331
Scale Considerations for
Ecosystem Management
Jonathan B. Haufler, Thomas Crow, and David Wilcove
Key questions addressedin this chapter
@Spat/al and temporal
man,lgemen[.
components
of scale that
are bnporcant
co ecosystem
0 Why careful consideration of scale is critical to ecosystem management
0 Criteria and suggestions for determining the extent of planning landscapes,
0 Considerations in identifying appropriate resolution of mapping or data.
Time.spans for ecosystem management planning
0 Time-spans for historical perspectives.
I(eywords: Landscapeplanning, spatial scale,temporal scale, mapping
332
I
].B. Haufler et al,lScaleConsiderations for EcosystemHanagemetu
INTRODUCTION
In fl'ds p/per on scale cnnsiderations,
ip{k_wh_g Re}' issue.:
One of the difficult
management
is the
challenges
facing ecnsv>tem
determ, inatio_'_ of appropriate
_-patial
and temporal
scales to use. Scale in a spatial
-;ense includes considerations
of both the size area or
extent
of an ecosystem
management
the degree of resolution
In the tempora{ sense,
activity,
" Spatial
'
as well as
of mapped or measured data.
scale concerns tbe duration
of
and tempora!cc,
system
° Criteria and suggestions
of planning landscapes.
of ecosystem
Scale considerations
management
reveals
the
are
to eco-
management,
" Considerations
tion of mapping
resource
n(sca!eth_t
important
to ecosystem
management
Why careful consideration
of _,cale is critical
both
natural
and
human
induced
disturbar_ces,
duration and time interva{s of successionaI
trajectories,
the appropriate
planning
horizon of future activities,
and the lengd_ of any historical perspective.
Areviewof[iteraturere[atingtosca[easacomponent
or natural
mp, ncnts
we addre>s
• Tirne-spans
" Times-spans
for determinir_g
in identifsing
or data.
for ecosystem
for hfstodca]
the extent
appropriate
management
perspectives
are inter, rally linked
resolu-
planning
to the defini-
hmv recently identified
this topic is, with considerable
focus of attention only within the last two decades. Early
plant ecologists such as Clements (I916) and Tanstey
(t924) addressed
questions about plant dynamics at a
-:land (homogeneous
group of plants) level. This focus
lion and objectives of ecosystem
management.
Ecosysteru managemerR
generally involves the consideralion of ecological, social, and economic objectives, each
of which wilt require
different scale considerations.
Although all three of these are important
obiectives for
dominated
debates
concerning
species composition,
stand structural relationships,
and successional
trajectcries through the next 50 years. Similarly, most animal
ecologists focused their attention
on the relationships
successful ecosystem management,
this paper will eraphasize the consideration
of scale issues primarily for
ecological objectives.
among
species,
or in
describing
stand-level
habitat
conditions required by different species. LeopoM (1933)
contributed
a broader view of wildlife-habitat
relationships by introducing
the multi-stand
concepts
discussed by Turner and Gardner (199I), Greig-Smith
(1952) discussed the importance
of scale in evaluating
the distributional
patterns of plants. However, it was not
until tire I980s that scale issues relative to resource manbecame
a major
component
BACKGROUND
FOR SCALE
CONSIDERATIONS
of edge,
interspersion,
and juxtaposition.
The importance
of
integrating
regional geography
and vegetation science
;',as first ternred landscape
ecology by Troll (1939), as
agement
2
in the ecological
Scale is defined by the size and extent of the observalions in time and space as well as by the resolution (i.e,,
pixel size or grain) of the measurements.
Scale is relative because it is either large or small compared to some
reference generally defined by an observer (Hoeskstra
el al. 1991)i The discussion of scale relative to ecosystem
management
requires
the use of numerous
some of which often have different meanings.
terms,
The use
literature. Schneider (1994:2) stated "In reading the ecological literature prior to 1980, I gained the impression
of scale terminology
has differed somewhat
between
ecologists and geographers.
Geographers
use the terms
ihat nearly all papers
before 1980 treat scale either
implicitly, or not at all." He attributed
this partially to
the relatively recent technological
advances in computars, geographical
information
systems
(GIS), and
renmte sensing tools that have facilitated
many new
tFpes of scale analyses,
Ecosystem management
has emerged
as a way of
addressing
increasingly
complex management
planning needs. It can be defined in various ways, but
regardless of a specific definition, it generally requires
large and small scale to describe the scale of a map, with
a large-scale
map depicting
less land area per cm of
map than a small-scale map. Ecologists have generally
referred to large scale as a description
for an aaalysis of
a large-sized area. in this paper, we define terms in the
following ways:
:nanagement
area
• stand:
management
will
developed
by the
neous
decisions
over a large
Gregg 1994). gffectix e ecosystem
n=..<] to utilize many of the tools
geographic
expandn G field of landscape
ecology,. As Wiens (1992)
noted, scale issues are one of the largest future challenges
to ecologists,
• size or extent: the amount
of area or length of time
contained in a delineated
landscape or time-span, or
a measure of its breadth and width or duration;
an identified
structure
area
with
reh:iivel>'
and composition
hnmoge-
of _egetati,.m;
• rcso[ulic, z: the level of dalai{, such as pixd size or
graininess, that is incorporated
into the mapping
of
an area or in the collection
of data;
.....
Biologicaland Ecological Dimensions
•
333
_.P. d, J. a,_ apt_roach tc_ecos_'s!en_managelnen_
fi_at h_vob,'es providh G for an approptiak,
mi× of
ecologica!
CO_mntmities
across a _laiil_in_
,
__
,Q_×,_,_
ldild-
scape;
,_",
• fhic filter: an approach
to ecosysteln
mar_agement
that involves a focus on the needs of indbAdual species or groupings
of snedes as a basis for landscape
p]ann _ng;
I
,
I
_°*'
• coarsescale:alevetofresolutionorgrainsizeusedin
I
_,o,,,,,
mapping
or measuring
data based
[
i
'
i
i
on units such as
large pixd sizes, large gram broad categories
etc,
• ¢fl_e scale: a level of resoh.ltion or gq'ain size used h't
,,,,_,,,,,,
4-
....
!
mapping or [neasurir_g data based on units such as
small pixel sizes, small grain, detailed data, etc.;
• bro_ldscale:aoareaofanalysisormanagementwitha
arge extent, containMg
acreage
a relatively
large amount
of
,,,_,_,.
or a long duration;
i
• s_a!IscaIe:anareaofanalysisormanagementwitha
small exlent, containing
acreage
or a short
a relatively
small amount
of
dLn'ation.
_,,
,,,
_0
_,,,_ _,,_° _°_ _,_
,_low we perceive an object or a phenomenon
is greatly
influenced
by the scale, both in space and time, at
which it is viewed. This rather obvious fact has impof
Fig. 1. biotic
Space/time
hierarchyclimatic
(at_er disturbance
Holling 1995)
for ._laat
processesand
events.
rant implications
for both science and resource management (Hoekstra eL al. !991). In many published
studies, there is no recognition
of the sensitivity of the
results to the scales at which the),' are conducted.
In-
some biotic hierarchy"
(1991: 6). Others have described
scale as operating
in a hierarchical
fashion. Spatial
deed, it is not unusual for the same question to be studied at many different spatial and temporal scales. In ecosystem management,
the approach used and objectives
being addressed will have a direct bearing on the appro-
hierarchies have been described for ecological diversity
from niches to biospheres
(Miller 1996), for ecological
classification from sites to domains (Ecomap ]993), for
disturbance
activities from small mammal influences to
priatescaletouse,
lfafinefilterapproachisbeingused,
then the planning
environment
should consider
needs of the specific species of interest. Typically
major floods (Bourgeron
and lensen
I994), and for
aquatic communities
from channel units to river basins
(Maxwell et aL 1995). Temporal hierarchies
have been
the
re-
sp_o I_o__*°_
source managers have mapped landscapes
into stands
on the basis of what they observe to be homogeneous
conditions
relative to their land management
objectires. However,
from the vantage
point of a small
mammal, the important
components
of a stand might
described for aquatic systems (Maxwell et al, 1995) and
disturbance
regimes
(Bourgeron
and Jensen
1994),
Holling (I995) (Fig. 1) depicted a combined spatial and
temporal
hierarchy.
Hierarchy
theory
provides
an
organizing
framework
to search for common
prop-
took completdy
different,
and scale related issues
would be very different, instead of looking at the cornposition and structure of vegetation
in a forest in terms
erties across broad classes of complex systems, including physical, biological, social, and artificial systems.
It is important
to recognize these hierarchical
levds of
of the overstory of trees, the critical scale might
arrangement
and patchiness
of the understory
ceous vegetation.
Addressing
a question at the
scale often leads to a faihlre of exp!anation
and
be the
herbawrong
to the
organization,
and
their
potential
influences
on
defining appropriate
scales,
lqow do we take fundamental
information
about
ecological
processes
obtained
at fine scales (e 4,
,.,,::rag conclusions (Wiens 1989, Turner 1990),
Turner and Gardner
(1991) distinguished
between
scaie and level of organization.
The3, defined scale as
_hys_c 1,g c,_ resi:'onse of }eaves to vle,,'ak :_,ie"e!s (f
ozone) and appl,
it to res g ;;,5,::- observed
,_t aroav!
scales (e.g., a iandscape,
a region, o_ eve_ !i_e enffre
'the spatial or temporal d'mens'on"
(1991 6), whereas
level of organization
was defined as "the place within
ecosphere)'_
hierarchical
Understaud
organizations
ng the properties
of complex
iS useful in addressing
this
-
334
qaestion
iransfer
J,B. Haufler et al.lScaleConsidera:lons for Ecosystem Management
(Paltee
1973, Simon
_f information
h>m
1973l. For exampk,,
e!_e Ireel
the
_,f ecL}]u<ical
,,:'ganizathm
to anothm- is nol a -imple addil_xe process, \ita! information
from lower _eveis in a hi_'rarchv
may be extraneous
icdonnation
at higher h,vds of
organization.
Furthermore,
hierarchy
can be isoIated
lhey operate at distinctly
levels in an orgaldzatiunaI
:he influencc*,
iegi:!v.._.,
,>
s_,cwtle.
f.u't_,r': -uch
_m dish_rbano.'
.>
!_h_bal dim._ie
.:h.mgu> (e g,, ice agc.:), shifts m >pcc_e_, ' rank:_,s and
interactions,
and e;_lution._ry
pi_,cc:,-cs
3
from one another
because
different
rates. A leaf, for
of hv.tu..trial
as wcll
RELEVANCE
OF SCALE TO ECOSYSTEM
MANAGEMENT
example, is sensitive to oranges in ligh t conditions that
can be measured
in seconds and minute;.
A forest
stand integrates this information
over weeks, months,
Ecosystems are not closed, _:clf-suppor t i_g syqems, hut
rather are parts of larger interacting
;ystems. Sightficant probDms
arise if ecosy*,tems arc treated as an
and gro',ving seasons, and its growth
responses are
measured
in these fimeffames.
Successional
change
_soIated "entity."
Rather, _he ecosystmns
in an area
:hOst be vimvcd in the context created of the broader
influences
_,m'rour_ding
light coc_ditions
over years
and decades.
At
landscape,
For example,
providing
habi-
each level in fl'_e orgal'dzational
hierarchy,
new organizing principles apply and new properties
emerge, so
properties
of whoie systems
cannot
effectively
be
predicted
from tile pruperties
of simpler
subsystems
(Allen and Start !982).
tat for forest interior birds oftei'_ involves identifying
within-stand
areas of sufficient distance from an edge
to provide protection
from parasitism
from brownheaded
cowbirds
(Molothrus ater) (Brittingham
and
Temple 1983, Reese and Ratti 1988). ltowever,
Robin-
What is an appropriate
area (extent) for ecosystem
managen'_ent
and planning?
In determining
extent,
numerous
factors should
be considered,
h'<klding
son (i990) reported that the Shawnee
Natiol'_a! Forest
was so saturated
with cowbirds from the surrounding
agricultural
landscape
that wood khru>h (H':daclchI_
t'cological, economic, legal, political, and other social
considerations,
all of wbdch are influenced
by different
factors operating
at potentially
different
scales. This
determination
must conqder
the rain.in'ram-size
area
,_stc/i_za) nests were just as heavily parasitized
(90ff_
parasitism)
at 400 In from an edge as at the edge, In
contrast, Stribley ([993) found that in the prhnarily
forested area of northern Michigan. cowbird parasitism
lJ_at is capable of addressing
the stated objectives of the
initiative as well as the cnaximum-size
area that can
feasibly be included
from the standpoint
of data
was not a problem for nests at any proximity to edges, ff
agricultural
lands or other cowbh'd foraging areas were
located
farther
than 3 km from the .a_e. l'hu:
collection,
data
storage
and
analysis,
collaborative
surrounding
lands can have a significant
influence
on
partnerships,
and the resources available to do the job.
The extent of the area can also influence the resolution
to be used in mapping or data collection. The data must
have the necessary or required precision to achieve the
desired objectives, but also be feasible to collect, store,
and analyze. No one scale of extent or resolution will
rdationships
occurring
within similar stand tvves m
two different landscapes,
and can significantly
influence the character of a habitat patch (Janzen 1986..
Maintaining
biological diversity, including! eenenc,
species, and ecosystem levels, is one generally identifled objective of ecosystem managemen_
Attainment
nmet all of the objectives
of ecosystem
management,
but instead,
multiple
spatial scales are likely to be
of ecological objectives, such as maintaining
biological
diversity, requires at least some minimum
spatial area
incorpora
planning
and time span. A fine filter approach
for maintaining
viable populations
ted into the decision-making
process. Project
can involve considering
a range of spatial
is typicalh" used
with sufficient
scales from a few hectares to millions of hectares. In
reality, however, decisionsaremostoftenmadeatlocal
levelsbyI-:mopleworkingontheground.
It is important
that these decisions be made within the broader context provided by a landscape
or regional assessment or
a regional
planning
framework
(Weintraub
and
genetic diversity and interchange
to avoid inbreeding
concerns and to provide
sufficient resilience against
demographic
or environmental
stocnasnci_ies.
In
contrast, a coarse filter approach, strives m provide the
ecological communities
necessary to maintain
ecosystem function and integrity, and thus provide for viable
Cholacky !991, Crow and Gustafson 1996).
Time-frames
to be used in ecosystem management
populations
of species within these ecolc gicaI communities over an appropriate
time span.
also require
careful cop, qderations.
]Re planning
_ime_fra::',_. for ecos.vstcm management
must consider
ti:e practical _ea/i_ies of _e:_ai, political, a_;d legislative
constraints,
but also the relevance and requirements
of
Thearearequlredtorneettheseecoio_
_alu>:ec_:ves
can vary greatiy, especially depending
on i_ov_ _,m_>ora_ considerations
arc faclo:ed into tin, >Lmnm " v:>r_
For example, maintenance
of population
viability _s an
ecological parameters.
Time-frames
for historical perspectives must balance the availability of information,
essential component
of ecological
biodiversity.
Population
viability
objectives relating
analysis attempts
to
to
.
Bioiogi(al and E(oiogical
i'cudic_
_hv
"7._]
pro{_./i':ii!v/_f
.-¢cw_7 '-_.,Lo,_
"_ h •
m'.'d
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rote
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hodqcapc>
pope,:
iron'Or{dill
._.h'et
tha{ typieal!y'
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iC
corli:crrls
,<
gia_
b
¢cJe, rat
land
ft)P
h£!le+spitgl
r, , c,4
._c_>_cnal
,-t-4sessme_/£
[earI1
k)P>g relative
to
,_ _ ch seldu*_
slay
viewed
from
<Dories
(i.e., the
cxeinet
or
r_:.:ords,
:,pan
Species
a much
shorler
-reties,
and
*, _{
the
This
for
new
has
ranged
populaeios:s
at a local
considt.r,
it is only
when
Based
of a
it {sees
• _"
before
on
that
fossil
discrete
species
the
spatial
of the
population
m_stafson
add
has
Mta.der_off
\Hired
fi_at the s;_ecie:-; borer - us exSn : [3), so_q_e e_ti:7 _>.,s, brcau<_e of human;
activities,
the extinction
ra_e
: -:weir<
. .-",-.
i,>Jav
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thi4
of populations
evolving
species
_<: -"f_ t' u;)rz]
"{'<_ _el
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as interim
continuum
becomes
_ht"
iii!t)ol-tafice
contributors
more
to an
apparent•
vmlallv
•
well
tem_(_ra{
eftor__
l!ia_ ad-
5 '._l_'_
tvelt'l
cemsMered
activity
affed
seal** q !;o_
has ?. direct
ae me
h:vel
some
-flee[
._um<l lpvvI
t_ut
CLtl_s_ut_lllg{ clP..*,-t
aud
eco_lorllie
ttoweve_
pra?_ical
veer;,
Kollasch
and
Crow
lga96h or
rnal*,a,_jemen_
ge_ out
;_re ,..,_,-
mana
m_x:h%
t()
be
Iha[ could
_oun(_
_,mc_t
_-uch as th_
lwery
as the a!!oca_ion
dy
oulcomes
it one
t roee:.;_eq
tool_ toe eco.;_:st_!m
model
and
1995)
HARVEST
th_ _ f, _r{.gt _llcces'¢ioi_
mendel
2
''
l,,._N[)t.
for _-va_ua_!n_
moll-
_a-a_es
CONSIDERATIONS
.o[;3:2+ai_i[oljll
ecosystem
_I1 ixl
,_re s'.Jtficietxf
at ch#ercrlt
el aL 1996'} are heti.mn
SCALE
4
,-
(I;l{_
-,_.,,.
ole fac_ ors ascii *,qlcr_*t tie 3.; a_ .. t_%,r_ } spatial
m _,, b_, nearly
10/) times the average
e_
c l_ "ear_ it•q "i <-h 1986_ Wh(';_
of a species
a_d
."a
1
*1%¢i'%1{v
_C'¢er.>al
Derision-support
such
landscape
[Js{l
d_e anal 5 .>is ,,vouh:t qulekly
Decisioo
models
[_
[)MI
%retied alld
5_v'I{1
level
,)racliea_
needed.
normuas_
oo[ll
all lhe ecc_Iot.lcal-
affected,
Some
,-.
"]"
,,_sitkm arm ins* ct population
Obviously
arc also
may exisl for
the llfe span
last
_
dm
commum_
or hand,
entia
the life
poputa-
sediment
potentially
_,\ h_h
"_ _.dH
_vtsr_v
i_111, throu_m
when
"life span"
,IV._I
qhl+'HhI
narve_,ung
activity
even
g
_H',CI'.¢ c a}:n*m>
° .-d, abili_h,q
o_ re:ee_erafloo
flow-
reported
than
a timber
change
CC{/>V
rode operate
10 years,
froi'a one to enmilk
era
of time
proces:',e_
same
t!u
actionsbeinv
_'_amlcs a{ the watershed
time-span
of
me
t.].!{ a
_._::_-,_
_'S H/U4[
seem
species).
as aggregates
j
plans.
survives
0991)
dlhl
oft ti_e proces_
.}t
1
uowetlves
cue management
example,
c*..
"
tm- I_ccd_ _f one
con_ c'rn:-, m plannieL;-f
might
of the average
Wilson
d_l{
of fores_
even
shor_
_i'iJ% lg_e fUl
biodh'ersiW
tl-
IC r- HFt'illV'I1¢g
>v<uc con_ldvratk)ll_,
>:gnificanl
• .,,,.
b_'m ,- U4_d
re*o_umm
[l<l_a hal:dlin
ecoloitoical
Managemell._
dt)pr{}.lcr_
.lDi[d{
calf
_.}--.
;l'CIql
-_ddr_>-.:
I_ ,'.hql[_rv
{
I%'olt(.
]k,:_i}]_l{l_ll
b_*{'tlH/
}t_ ur
51!1"
'
_',_!},1
{irl_'*_
__iu m,h'_/
Ecos_,'g_,il
late-
n
rlll{'_
thus
an
e_er
differeot
with
time-span
a species
period
of
Ecosystem
!v
,l>stlrrlm_
plan-
a I00-year
associated
applie_bility
into
exist
chose
.q.,pro,u
I/_'Ct'%%O+V
dress
forexanlple,
impacts
_,'itdlife
and
]0Df_-teri't_
afjctlcies
c( r s sten
arid
,_if_ng Individual
nMIJstic
is a relatively,
evob.,es
of ecological
.
¢{tq_t?_l_llll_.. oll t_u
al(hotl_!,
a
_ _I{1"-.
•
v
.lu[=1]]
dIh.r
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mw
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_',';_l]
.!r_tl
varv
_{,ar._v !llh.r
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viability
()i
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_t_p_h
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Ct{).,V:D[,OH l!IdKId_'t'H]t'{_(
adctJud_e
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_.
t,{ al,
levi
mak{i_,.'.
._ :r
['))4_i
[_t!?!
[
[(li.,_i!,om
c.111
v_-'Ct
UdM',
q
h.
ttq
Managers
population
a bhmd
as
1993)
of most species
)ears.
questiou_.
ll
lh.1{
7(l¢$pv'ct,_;
the contex_
Ehrlich
v{-
.'!-._-:_,_lc/'_._'!,llc.-,
_,-,.
flre*i¢I_a,-s_lil*cF_l},,
nl_/l
o.li_ItHiu
tile afeaq
]ar,_er e×{ent,
(|retest
time
Thtls.
firqt
diversity
r_'!-,t!!_
kJH/CI
' .....
lIldVIhlt,'c
__I'IqV>;{CIU
<malvsesMr
vib
actual
100 .ve'_rs
_t
r/alJ
a[_proxtloatu
ev,.,ll
on
h_rrsh.;
aft,2.
_{ibt_h
Viability
PCrFIvICI"
{ II!!_'M_UI-.
o
ts'eJ]
..
.,,,
";e d{ld
[lk_[iulat{(Hi
lo_x¢
[_.l_'o,_r/:a_>'_
x.-2
than ('al_adl0,_l
the PacificN0r[hwest,
lvvels
" '
.lo
mana}Semont
:m_bvr-har,,'est
V
]dF}'_¢q"
ect2s;Jster_
reflects
,.IS
_: t
_/_'r
I(_qeH and
Lye dr'lee,milled
for a_se4sb_:{
decbsion
. "c'.
a
haIe
lc,'_l)ol'_[
a tim_,-span
0_i-
335
'-H_.ic!
,.l}_isre prJate scah>, ca{_ the
{_[
elf
Mai_taini_}
_:iJres:;
a
},st
' (hy<4elV
.It
a_la[l,
_r
rt_qlail'cmeilb;
t_lus[ be dddl-e_._,
•
to {p,{s
speciesData oi1 hare
{!I/_Ft
";}_t'v[t'.;
into
q
[of
].
}HI' U]<_v.'sh(*e
thc4t'
4
.u'ea
oveF
b}' _5"I]x _xo}_tlld{iOllS.
_..:.,red
.'.CLIF
I '•
_.i_l.ll{ei'
thll'e
q;_ ._+','-!l/}e i_dl'e }/,_'.a!_l
>,'d .1{ _c,_l. v q app_o?rbltu
r: .!tliFed
effo!_
(t*rlqikicFat{o/1
\r{'
pi2;/I
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alh[{_oxvt}_L'VI't'I4!C{Opt_}'U-
{I_ a _altlcb
.IJk'qUd{d
t.,
i'__!i'C
-.'u_;t
/
till!<
the planning
51]_X_!IOC
XI("
' _
_,_ .mec_e.!
O_ ";I/i_D{',_I_I*.
]a..Ugillf{
2}-i
o_l_qe_.'c
,_ c!
Dimensions
nlallagellleFlt
the extent
t;t._
:,/_(TLzld
process
of the planning
; ¢' 3<_I(+';_"_'_
....
include:
hmdseape;
!_
_i7_
5'_
336
•
I.B. Haufler et al,/Scale Considerations for EcosystemManagen_ent
•
file appropriate
ruaoiuthm for mappir G or tiara cob
lection;
tl'_e planning timc-sF, aa; and
Boi,_c Cascade Corp., pcrs, comm.)
V';itbin each of
{i:,.,sv p!anning land,.capc>, an eco._yqcm diversity matrb, (t laufler 1994, 1995, I Lmth, r et al. I996) ;,,'as then
•
the time-span
develupecl
ecosystems.
4. t
for an historical
perspective
Extent of Planning Landscape
Io characterize
and quantify
the forested
This matrix provMes for the quantification
of ecologicalland units within ti_eplanning landscape.
An additional
criteria
for delineating
planning
land-
One of the first steps
in ecosystem
management,
following
an initial identification
of the participants
and management
objectives, is determining
the extent
a _d bou _darv(ies) of he p a ruing landscape
(Ftaufler
scapes is that ecological
land units within the landscape should be consistent
enough
throughout
the
landscape
that they have an acceptable
level of variability for key habitat variables or characteristics
(Roloff
et al. 1996). This involves considering
the appropriate
size of the landscape,
and the boundary
criteria.
"
tiaufler et el. (1996: 20l) listed the following as criteria
1994). In other words, all stands that comprise an ecoIogicalland
unit should have similar enough compositiOl*t,structure,
or other characteristics
so that habitat
for delineating
variables that describe the unit have small enough
ance for determining
habitat quality or quantity
varifor a
species.
Other
with
ecological
• Similar biogeoclimatic
potentials.
• Similarhistorical
vegetation
boundaries:
conditions
disturbance
structures
that influence
site
regin'msthalinfluence
management
initiatives,
different objectives or organizational
structures,
used different scales. The Federal government
and species compositions,
" Adequatdy
sized landscape
ranges of habitat conditions
ecosystem
eated the Interior
to provide
sufficient
to assure population
Cob.reibis
Basin Ecosystem
meat Project as a planninglandscape
management
assessment,
focusing
have
delin-
Manage-
for an ecosystem
on the Federal land
maintenance
of the majority of native species that
historically occurred in the planning
landscape, ex-
holdings
included
eluding certain species such as megafauna.
Megafauna or species with low population
densities will
require analyses at broader scaIes where contributions from landscapes
are aggregated
to address
the scale gradient, the Watershed
Analysis
tion Team (1995) recommended
conducting
analysesbasedonwatershedsof4500-52,000hainsize.
No single scale exists for describing
population
patterns
or diversity
(Levin 1992, Noss t990). The
inherent complexity
of landscapes
results in a mozaic
of both micro- and macro-site conditions
that provide
• Recognition
maintenance
of these species,
of maximum
size to avoid
practical
op-
(Quigley et al. 1996). The assessment
area
more than 58 million ha. At the other end of
Coordinaecosystem
ecosystem
erational limitations
in terms of data management,
implementation
restrictions, and number of cooper-
for the range of patterns apparent
at different scales.
Turner et el. (1994: 76) stated "View the Iandscape as a
ating
whole
and
pattern
at multiple
Ecomap
landowners
necessary
(1993) and Maxwell
for successful
plans,
et al. (1995) provide
ahier-
use landscape-level
indices
to measure
scales. Do not focus solely on single,
archical classification for boundary
determination
that
can be used to define a plarming landscape.
Haufler et
al. (1996), using the above criteria and classification, advocated using the section or aggregates
of subsections
simple concepts like patches and corridors, and recognize that these concepts are scale-dependent."
These
views are not inconsistent
with a hierarchically
based
delineation
of landscapes
for planning
purposes.-
level (equivalent
to Bailey's subregions
(Bailey 1995,
1996)), to provide an appropriate
landscape
size to
meet ecolo_cal
objectives while being operationally
functional. In Idaho, Haufler et al. (1996) described the
When a planning
landscape
is delineated,
it should
contain various descriptors
of ecosystem
complexity
within the planning
landscape,
and allow interpretation of this complexity
into larger-size
areas m the
Idaho Southern
Batholith
aggregation
of subsections
within the Idaho Batholith
hierarchical classification.
Most past management
political and ownership
1994). In Washington
sections was selected
landscape
comprised
of an
containing
2.3 million ha
Section (McNab and Avers
State, an aggregation
of subto delineate
the 1 1 million ha
decisions.
ecosystem
planning has utilized legal
boundaries
as the basis for
Although mese boundaries
remain critical.
management
has added new ecological cri-
Central East Cascade planning landscape
(D. Volsen,
Boise Ca-cade Cort_ pers. co n _ t In Minnesota,
the
entire Northern
Minnesota/Ontario
I eatlands Section
teria to _and managemcnl
planning. -!he<_ new criteria
require tne consideratic
_ al'td Idel/!ificdt{o_ ef coo[ogical aoundanes
ann scales 1he soaai and economic
was identified as a planning
landscape
for an ecosystern management
initiative in that state lB. Kernohan,
objectives of an ecosystem
incorporate the ecological
managementinitiativemust
boundaries
of the landscape
Biological and Ecological DimensioBs
pi._rmin_;unit:bu{_i]l
usua!ivret]ect
_b, poiihc_! stiuc{ures, and soci/[
economJcmilrkinfluences. ,\l! of
a sbecics
rvsokldon
337
of concer_
{o identify
becat_se of ,:1 lack of sufficient
the presence of suitable habitat.
these .opcrab._at multipht-spatia! scales, For t._xample, a
local community
will have many componcnb
of its
In a sindlar example, Capon el ,_,l.(1994) compared
Hie nlappingresohltion
used by a Gap analysis project
quality of life influenced
b? the surrounding
landscape. The surroundh_g
landscape
_ill largely deternline the scenery, recre_iionaJ opportLmitJes,
oppor tu-
in Vermont (I00 ha pix{'ls) to a liner scale resolution
[hat mapped stal_ds to an average size of 9.5 ha. They
foui1d that with the finer scale resolution
there were 68
irides for firewood cutting
wella'vcomme"
a ex raco
connnunity
types on a 62,000-ha study
analyzed
witl_ species habitat models
or mushroom
picking, as
Iost
pdor
oc c m_iv.c-
area that were
to support
98
dity-based
industries.
This same landscape
will have
addffional ob}ectives placed oll it by state authorities
to
meal objectives such as water quality standards.
Addi-
bird species. Usinga Mmilaranalysis
a6 of the 68 commumty
types were
the 98 bird species were retained.
tional
national
priorities
for wilderness,
mineral
v,xlaloration,
or other objectives
may override
local
objectives.
Desires at the local level for commoditybased industry
are dependent
on the economics
of
scale of resolution
can Dad to different and often mJs*
leading
results
of both available
ecosystems
and
associated species.
On the other hand, using data at too fine a scale can
global markets. Conversely,
there is the possibility that
local restrictions
on condlnodity
extraction
may raise
c<_sts of a loca_ supply of commodities
to h_gh enough
overwhdm
data storage and analysis capabilities for
most planners.
One landsat thematic
mapper scene
(185 km x 170 kin) for 7 bands ata 30 m pixd resolution
kvels lhal supply is shifted to more distant sources,
Whether or nol this happens depends
upon a complex
,t of economk:
factors, but it has the potential
to
'export" emqronmenta[
problems to other places with
requires
2,I4.3 megabytes
of computer
memory
(C.
Campbell,
Boise Cascade Corp., pets. comm.). With
current
technologies
leading to capabilities
of a l-m
pixel resolution,
with potentially
900 times the data
less stringent environmental
safeguards,
Meshing the social and economic _v-it h the biological
and physical worlds remains a major challenge facing
resource
managers.
Significant
advances
have been
generation
of a 30-m pixel, the data support needs can
become staggering. As computer speed and data handlingand storage capabilities expand, thesebarriers
may
disappear.
At the present, however, real limitations of
made in integrating
these disciplines under the general
rubric of ecological economics
(Constanza
etal. 1991).
In this emerging science, great importance
is attached
to the interaction of environment
and economics and
hardware
and software relative to the planning landscape area exist and must be recognized.
Another example of resolution delineation
was discussed by Schneider
(1994: 27). He stated "The length
to themes
synthesis,
of the seacoast
that measured
4,2
common to our chapter such as multi-scale
hierarchical
theory, and interconnections,
Resolution
Issues
for Mapping
with the Gal:_data,
kIs, and ordy 6,' of
-fhus, too coarse a
as measured on a map will differ from
by pacing along the beach because the
map measurenlents
are at a much coarser scale than
pacing. The customary
view of this difference is that
thebeachhasatruelengthandthatmeasurementwith
a meter stick is closer to the true value than measure-
or Data
Collection
ment
with a larger unit,
such as a kilometer
stick. But
The resolution of the mapping
units and data used in
ecosystem
management
can have a significant
influonce on the conclusions
of an ecosys_tem analysis. For
example, Gap Analysis has used a fairly coarse scale (1
how far do we take this? Should we say that measure.
ment with a meter stick is also inaccurate,
and that a
centimeter
stick must be used instead? How small a
stick is necessary to obtain the "true" length?"
km pixel) it1 some of the state analyses. This means that
each pixet can be assigned only a single vegetation or
ecosystem
characteristic.
At this resolution,
plant
For stand delineation
or measurements,
similar
decisions must be made. Fine-scale dafa, such as a l-m
pixelresolution,
theoreticallycandistinguishal:rngap
communities
that typically
occur in relatively small
patches; for example willow (Salix spp.) along riparian
zones, will never occur on a map of vegetation
types,
S>_ecies dependent
on such Lqantcommunities
such as
the yeliov, ",_arbler (De_dm!c'a petechin) in much of the
',",estern v. >. will not be ,. LD&IUZt._I as havin_ any
in canopy coverage in a stand Of trees. Should all of
these gaps be mapped out as separate stands? For most
purposes, this would present _oo fine a resolution
of a
!andscape
to interpret
relative to mapping
_ f 'ben ogeneous" stands. At aome fine scale of resolution, addit:.:.,nal precision ma_ be grealer thin that discerned by a
available
species
habitat,
even
though
relatively
significant
amountsof
habitat may exist. Thus, usingaverycoarse
scale of analysis, yellow warblers might be identified
as
of interest,
if a fine filter assessment
utilized.
For example,
(Cervus elaphus) would
is being
it is very unlikely that an elk
respond to a 1-m gap in canopy
338
J,B. Haufler er al.IScale Considerations for Ecosystem Management
coverage, t oweve
a vole (Alicrotas spp.) might select
a :0-m patch of grass in an und,erstory I", hat then is
time-span for animals that are both diurnally
and
nocE_rmlllv active can }tad to ii_accLlraic, descriptions
appropriate,
mappii'_g of i0-m gaps, 5L)-m gaps, I-ha
,,>perdngs, or 5-ha epeni_'_gs? The larger the clisccmti-
of habitat use and in_portance,
scale,
vegetation
structure,
nuiLy ic_the vegetation
that is accepted,
the greater wilI
be the variance around parameters
for descriptions
of
status, and other
withh_ a season,
stalrds. The finer the resolutiml, ttae more homogeneous the overall star_d delir_eations, up to a point where
temporal patterns rnay not be consistent even in fairly
local envirorm_ents
depending
on influences
such as
additionaI
:vithin o
elevation,
temporal
precision
is actuaEy
sampling
variation
e'w se homogermc us s a d conditions
At a different
composition,
temporal
nutrient
factors change seasonally,
and even
as plants grow and senesce. These
aspect, shade, and soil moisture.
At a longer
scale, the vegetation
being sampled
will
The concept of inilaimal area of a stand (MudlerDombois and Ellenberg
1974, l_;arbour et al. 198(1) has
co_siderab]e
relevancy
to this resolution
question,
Thus, resolution
of data and mapping
precision are
change
annually
with growth
and
maturation
of
stands, and successional
change. At longer time scales,
differences
haxe keen noted beeween ecological time
and evolutionary
time. Schneider
(t994: 28) disting-
critical considerations
in classifying
and describing
ecosystem management
landscapes. The specific use of
ihe classification
will help to identify an appropriate
ulshed these as Ew.Hutmnary time operates on a longer time scale, over which charges
in gene frequer<y
can be described as trends, rather than a r_oisy coming
resolution.
The resolution
of data and mapping
is
Ltstlally set by what is available
within a plannir'_g
,_d_et
with little consideration
given to the assess-
and going of alleles. Ecological time operates
on a
shorter time scale, over which changes in population
size occur with lit le or no change m gene frequency/'
meat or consequences
of using tire selected scale.
Resolutior_ considerations
also operate for temporal
components
of ecosystem i:aar, agemerLt. Ir_mordtoring
or data collection,
the sampling intensity
or irLterval
should consider the periodicity of the process or phen-
Ti_e significance
of all of these temporal effects or_ the
information
being
collected
by the sampling
or
monitoring
should be consklered in samptir_g designs.
4,3
Time-spans
for
Future
Planning
omena
being sampled
or monitored.
For example,
measurement
of humidity
in riparian
zones in the
Western
United States reveals more variability
on a
Maintaining
biological
diversity
and ecological processes involves considering
time frames that are often
hourly basis (Fig. 2) throughout
a day, than variation
from different locations
at any one point in time (R.
Daneby,
Boise Cascade
Corporation,
pers, comm.),
far beyond
traditional
planrdng
horizons,
Genetic
components
of biological
diversity may involve the
analysis and planning
for multiple
generations
of a
Thus, im,'estigations
of factors ic_fluencing humidity in
riparian zones would need to account for the temporal
chm_ges in humidity
throughout
a day in any mean-
species to assure that adequate heterozygosity
of gene
pools are maintained.
Such time frames are beyond the
practical realm of resource management
decisions, yet
ingful analysis of site effects. Similarly, habitat use by
many animals is strongly influenced
by daily activity
patterns,
Beyer and Haufler (1994) displayed
how
failure to monitor habitat use throughout
a 24-hour
ecosystem
managers
must factor these long-term
concerns into the planning process,
Another
example
of the importance
of temporal
scales in ecosystem
management
invoh'es
the exchange
!!}
_o _
_o [.
__0o_
30-}.
I
._ Z
LT_mL-_ap2ZJ
f
_1_
f
7
_. ,_
,
_
...........-- _, _ ,_ * g _ ,_",-_ _ _"' g ,,,° _.___"__
r_,_,,I_,_}
Fig, 2. Graph of relative humidity (RH) recorded hourly at two
distances from a stream in Western Oregon. R. Danehy, Boise
Cascade Corporation, unpublished data.
of genetic
information
and
provisions
for
metapopulations
of a species. Noss and Cooperrider
(1994) and Harris and Gallagher (1989) discussed the
importance
of maintaining
corridors
that allow
connectivity
of similar habitat, such as old growth, to
facilitate dispersal and genetic interchange,
They felt
demographic
and environmental
stod'_asticity
among
that this was important
to avoid problems
with inbreeding
or stochastic
population
fluctuatior_s
that
could disrupt or extinguish metapopulations.
This concept views the landscape
as a static condition,
where
metapopulations
aI'e con inuouslv, linked by. corridors
of similar habiiat conditior,.
Old gro',v_h corriatq
- '-'_" S
would provide connectivity
among late successional
stands in a laadscape, assuming animals used the established
corridors,
but they would
also
isolate
earlier
Biologicaland EcologicalDimensions
';uccessiorta! -;lands in the landscape, as it is impt, ssible
{_.provide c=m_ectivity of all late s_._ccessio_aldcl',e_d...nt mctapc_pulatlous and early succes.4onal rectapopulation o, at the same time. While dispersal
capabilities of old growth dependent
versus early
_,uccessional dependent
species have not beevt
extensiv,ely examined, metapopulatior, considerations
point to the imi'ortance of addressir G all c_,_:necti,,ity
co_cerns, t3y incorporath G a temporal scale inlo the
p!an, com_ectivity of diverse populations at approprlale time intervals to protect against inbreeding
c;,_woms ear_ be factored it, to the plan. Camp et al.
(1997) and Oliver et al. (1997) diacussed a landscape
analvsi_ that showed dynamic shifts over time of
refugia for early or late successional species, and that
through changing landscape configurations, cormectivity of alI metapopulatim_s can be achieved. Thus,
lemporaI consideratior, s can provide criticallinkages in
landscape planning designs.
.,',.nother consideration for the planning time-span is
the duration of the plmu'dng horizon, relative to the
duration o f the disturbance regimes of the primary
ecosystems in the plannir_g landscape. As mentioned
previously, returndntervals
for fire disturbance can
range from less than 25 years to over 1000 years (Agee
I993). Tides cycle more frequently than daily. Major
flood oventa may occur at very irregular cycles, but
aquatic ecosvstems may take hundreds of years to
recover. Planning for 1000 years is unrealistic from a
pragmatic managemer_t standpoint. Yet, the sigrdficance of 1000-year disturbartce intervals should be
factored into ecosystem mar, agement plans for such
ecosystems, without overlooking the importance of the
more frequent, often, less severe, disturbances.
At very long time-spans (i.e., >.1000 years), the effects of shifts in species ranges, an.d climatic events such
as global warming or cooling, could produce changes
in species interactions and competitive advantages,
and change the basic composition and structure of ecological communities. Some would use such information to argue that any attempts to characterize or
classify ecosystem compositions, structures, or distributions are inappropriate, However, the necessity of
providing a reasonable projection of ecological outputs
from a planning activity overrides these broader
temporal scale views of ecosystem dynamics.
339
_f variability is being defined? I fuman altoratiort _,f
natural disturbance regime'; has been dramatic over
the last 100 2il0 year_.. Even priur to this, indigenous
populatiorLs were significantly influencing ecosystems
to varying degrees. With some disturbances occurring
at intervals of 500+ years, range of variability can becon',e intermeshed with shifting species distributicms
and climatic changes, as .!iscussoJ above.
Ecosys_ei'o mauagement must factor ill an understanding of the influer, ces of historical disturbances on
the occurrence, structure, aud functioning of compoherd ecosvsteros in the landscape, and undorstaud the
relationship
of these historical disturbances
with
recent anthropogenic
disturbance. Each landscape
must be evaluated as to the appropriate reference timeframe for an understanding
of historical disturbance
regimes. In the ",Western United States, an historical
perspective might focus on a time-span of 100.400
}'ears ago (Steele I994). In the Eastern United States,
because of the earlier extent of dramatic anthropogenic
influences, the appropriate time-span for analysis and
quantification may be from 200-400 years ago.
Incorporating historical perspectives into ecosystem
management hassevere restrictionsffomavailabilityof
data. Typically, forests in drier landscapes have
preserved more stumps acLdlogs that cau be used for
dendrochronology
studies, but in wetter environmer, ts, sources of data may be very restricted. Morgan
et al. (1994) discussed sources of information on historical disturbance regimes.
5
SCALE RECOMMENDATIONS
All efforts at ecosystem management at a landscape
scale are new approaches, and as such, should be
viewed as experimental and adaptive programs. This is
not to imply that landscape approaches are not based
on the best available information, or that they are in
any way inappropriate
management directions, but
rather, thai their results should be monitored and
adjusted as needed. Scale recommendations
fall
directly into this category. Little empirical data exist as
a direct basis for designating appropriate scales. However. various recommendations
can be propose<_ mat
may serve asinitial targets for adaptive management.
Tire extent of an ecosystem managemem initiative
needs to balance the various obiectwes ann constraints,
Historlcal Time-span Considerations
as discussed previously The secnon levelor aggregates
of sub-secnons v,'ithit; Ecomap 1993) seems m be a
Perhaps less ominous but equally challenging is
d,_.fining a:: appropriate historical perspective to use in
ecosystem management, To meet ecologicalobjectives,
understanding
historical ranges of variability can provide important reference points. However, what range
reasonablebal_,r, ceofrnicdnum*xzetomeetecological
ok,jectiv'-*s with a maxzmum slze to mam_ a:n an acceptable amount of variability in ecological communities
and to involve partnerships
and data compilation.
Terrestrial components, such as cells within an eco-
4.4
3't0
].B. Haufler et al,/Scale Considerations for Ecosystem Hanagement
system diversity matrix (Hauf/er et al. 1996), should
have acceptable levels of variance at this scale, with
most of the biodiversity of the landscape occurring in
maintainable populations. Aquatic components should
also be able to aggregate to this scale, with watersheds
as one level of identifiable units that can aggregate up
to the landscape level (Bailey I996). This extent of a
landscape should also allow data to be collected and
analyzed at resolutions that are sufficiently finegrained to meet the needs of fine filter assessments,
Resolution of maps and data collection should be
detailed enough to meet the desired objectives, but
allow for compatibility with available storage and
analysis systems. Landsat imagery at 30-m pixels can
meet the needs of many objectives, but may not be
detailed enough for some fine filter assessments. It also
lacks the ability to discern many kinds of information
that may be needed
in ecosystem management
including understory characteristics, soil typing, and
stream classifications. Stands should be mapped at
resolutions that provide sufficient description of cornmunity and habitat features to allow for all components of biodiversity to be accoun ted for. If resolutions
are too coarse, then components of biodiversity can slip
through the heterogeneity of stand conditions in the
mapping, and ecological objectives may not be met.
Even mapping resolutions of 5-10 ha will not typically
identify many small or linear habitats, such as narrow
probabty
more reasonable
to target
ecological
conditions that are oxpected to be needed to meet
ecological objectives, and assure that short-term plans
provide for the capability of prm,iding these conditions
in the future. Thus, plans should strive to meet shortterm specific objectives, and assure that longer-term
objectives are not precluded.
Historical perspectives of ecosystem management
are well summarized by Morgan et al. (1994). They felt
that the historical ranges of variabUi ty of significance to
ecosystem management
should be "assessed over a
time period characterized by relatively consistent allmatic, edaphic,
topographic,
and biogeographie
conditions" (1994: 94). For inland forests in the Western
United States, Steele (1994) recommended a time interval of 100-400 years for defining historical disturbance
regimes. In other areas this time interval may need to
start further back to factor in the earlier influences of
European settlement.
bands of riparian vegetation. Such linear habitat may
be the primary habitat of species such as the previously
mentioned yellow warbler. Too detailed a resolution
may not allow functional homogeneous
units to be
mapped in a landscape. The appropriate
mapping
resolution for a planning activity must be carefully
evaluated relative to the full suite of management
objectives. If the desired level of resolution cannot be
obtained at present due to budget or technological
limitations, then the potential implications of this
should be clearly identified and stated.
Planning time-spans should reeogmze degrees of
expectations at increasing time intervals. Relatively
detailed plans are often expected for the immediate
future (e.g., 10 years). Less detailed plans, that still
prescribe specific targeted conditions and their loca-
6
CONCLUSIONS
1.
Scale considerations are a critical component in all
ecosystem management efforts, and include the
extent of the planning landscape, the resolution of
mapping and data collection, the time-span for
the planning horizon, and the time-span for an
historical perspective.
2.
No one scale will meet all objectives of ecosystem
management. Rather, appropriate scales must be
3.
4.
knowledge, and technologleswillundoubtedlycharGe
dramatically over the next 20 years makes unrealistic
the expectation that detailed plans will remain in effect
for long time periods. For longer time periods, it is
L
The spatial extent of planning landscapes must be
large enough to address adequately population
viability, biodiversity, andothersuchcomponents
of ecological objectives, but not be so large as to
cause either too much variance in delineated ecological communities
within the landscape, or
make infeasible the building ofcoflaborative partnerships or databases. The section level of Ecomap
t1993L or aggregates of subsections, may be an example of this balance.
tions on the ground, might be expected for a 2050-year horizon. Plans for longer than 50 years tend to
portray trends for the conditions that need to be
present, and descriptions of how they will be provided,
but not to the same degree of specificity as for the
shorter time frames. The realization that demands
selected for the various objectives, and linkages
among these scales identified.
Analyses at different scales, or at the same scale
but in different landscapes, can lead to significantly different conclusions. Thus. many ecosystern management
relationships are scale and/or
landscape dependent.
-
The resolution of mappmgand
data q_ou!d be de-
tailed enougil to allow for the identification of
landscape mapping units (e.g., stands, stream
reaches) that can provide descriptions of the habb
tat requirements of species, but allow for a reason-
;
<
Biological and EcoLogicalDimensions
able identificatlon
of homogeneous
conditions
for
planning.
Pixel sizes of 30 m, oi" mapping
resolutions of approximately
2 ha rnay balance these
needs
6.
for many
Planning
Costanza,
time-spa
is should
focus
for short-term
all manage-
on providing
objectives,
while
also providing
for conditions
to be produced
or
maintained
to meet long-term
objectives. The duration of successional
trajectories and disturbance
regimes
7.
must be factored
Historica!
perspectives
into planning
time-spans,
must
time-spans
address
that allow for historical disturbance
regimes to be
considered
prior to dramatic anthropogenic
alteration, but balance this with the length of time that
data on these disturbances
can be generated.
In
the inland forests of the Western
United States, a
100-400-year
(Steele 1994).
perspective
may
be appropriate
ACKI_IOW[,EDGEI_ENT$
A number
of people
have provided
useful
guidance
and input in the development,
writing, or editing of
this paper. We wish to acknowledge
and thank the
assistance
of Gary Roloff,
Rique
Campa,
Dean
Beyer,
agenda,
R., H.E. Dali' and J.A BarthoIomew.
and policy recommendations
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TI'[_
AUT["[O[I-$
Jonathan
B. Haufler
Boise Cascade Corporation,
P.O. Box 50, Boise, ID 83728, USA
Thonla$ Crow
USDA Forest Service,
North Central Forest Experiment
Station,
Forestry Sciences Laboratory,
5985 Highway K
Rhinelander,
WI 54501,
USA
David Wilcove
Enwromnental
Defense Fund,
1875 Connecticut Avenue Suite
Washington,
DC 20009
1016,
|
J